Cumulative survival, progression rates, APOE gene allelic frequency, and neuropathology profiles of Alzheimer's disease (AD) cases.A, Kaplan–Meier cumulative survival analysis and (B) duration of disease of cases with pathologically verified AD that were initially referred to National Prion Disease Pathology Surveillance Center with rapidly progressive dementia (rapidly progressive AD [rpAD], n = 32) and cases of slowly progressive AD (spAD, n = 34) collected at New York University Alzheimer Research Center (17). Statistical significance for difference in survival at p < 0.001 (∗∗∗) was determined with the log rank (Mantel–Cox test). C, severity of pathology classified according to National Institute on Aging–Alzheimer's Association guidelines for the neuropathologic assessment in rpAD and spAD: “A” indicates phase assessment of the Aβ deposits severity; “B” is staging neurofibrillary tau pathology; and “C” (CERAD) is scoring the extent of Aβ plaques (73). D, frequency of e3 allele of APOE gene allelic polymorphisms in rapidly and slowly progressive cases of AD. Statistical significance was determined with two-tailed Fisher's exact test.